In the preparation of samples for MALDI ionization, an analyte sample is typically intercalated in a matrix material on the surface of a support plate. A laser is then directed onto the targeted sample on the support plate in order to desorb energized matrix and analyte particles, which then causes ionization of the analytes through electron transfer reactions.
Carbon nanotubes have recently been used as a surface coating on MALDI sample target plates due to their exceptional physical and chemical properties, such as their hydrophobicity and their capacity to absorb ultraviolet radiation, which is the typical range of wavelengths used for the laser in the MALDI method. The carbon nanotubes are currently deposited over the target sample plate by chemical vapor deposition (CVD), which leaves a thin film of randomly ordered single or multi-walled carbon nanotubes that covers the entire exposed surface of the target plate. While the carbon nanotubes may be a useful material even in this spatially non-specific and relatively disordered state, it is believed that some of the beneficial properties of the carbon nanotubes are not necessarily being taken full advantage of in the MALDI process when used in this way.